The rally started at 2:00 pm Moscow time and is expected to last for about three hours. Police say the gathering is passing off peacefully and without major incidents.

However, law enforcers stepped up security in the city as a precautionary measure.

On Tuesday, thousands of people marched in Moscow and St. Petersburg, some to protest at and others to celebrate the outcome of the country's parliamentary elections, which were won by United Russia, the party of the incumbent president and prime minister.

In central Moscow, opposition protesters complained of alleged voting fraud, and faced off with supporters of the majority United Russia party.

Riot police were dispatched, arresting around 600 people, including several prominent opposition members.

In St. Petersburg, at least 200 people were detained during the demonstrations.

Tuesday was the second consecutive night of large protests in both cities, with smaller rallies elsewhere